Unity and diversity among human beingsChapter A

Classify in a chart, common characteristics and differences between you and a classmate

Study of a family tree (book page 13) : from which parents Gaëlle might have inherited her red hair ? And what about the spacing among top incisors from Tom and Louise ?
Why some characteristics are qualified as inherited characteristics ?

You can get scars after you have injured yourself. Your children will not be born with the same scars.
At birth you can not speak; you have to learn by listening to your parents and copying them. If you never hear anyone speak, you will not be able to develop language.

Questions : State two human characteristics that are determined by the environment. With your own knowledge, can you give more examples ?

1) Use the following words to complete the blanks : genetic, nucleus, inherited characteristics, microscope

The ................. information is located in the ............., and it determines all our ...................................................................
What is the support of the genetic information ?
To answer this question, we’ll study cells. What kind of tools can we use for this study ?
We can use a ...............................

2) Read your book page 50, and find what molecule is supposed to be the molecular support of the genetic information.
Your answer (in french): .................................................................................
Can you translate your answer in english ?

Lesson 2

Vocabulary : nucleus, cell, genetic information, DNA

C) The cell nucleus

Lessons 3

Vocabulary : chromosomes, genetic information

D) Chromosomes structure

Exercise : watch a video and tell what you understood (hind : few words have been written on the white board)

Lesson 4

Vocabulary : DNA, chromosomes, cell, cytoplasm, membrane, nucleus

E) The genetic information

Lesson 5

A gene is composed of DNA. It’s a part of a chromosome that determines an inherited characteristic.

Exercise 1 (oral activity)

Questions about genes and different characteristics
a) Where are chromosomes found in the body ?
b) How many pairs of human chromosomes are there ?
c) Which of these characteristics are totally inherited ? Body weight, hair colour, blood group, eye colour, skin colour, academic ability, inherited diseases.
The other characteristics on the list may be affected by something else.
d) What else might they be affected by ?

A gene is composed of DNA. It’s a part of a chromosome that determines an inherited characteristic.

G) Billions of different people and only 23000 genes : how is this possible ?

Lesson 7

The slight differences within an inherited characteristic (e.g. eye colour) are controlled by different forms for a same gene which are called alleles.

H) All our cells have the same genetic information : can you explain that ?

Exercise

[Execute and think]

Let’s imagine a species with only two pairs of chromosomes.

1) With our model, try to organise a cell division that will give two new cells with the same genetic information (one pair of chromosomes). Then, do a diagram to expose your hypothesis.

2) If one of these cells divide into two new cells, how will it be possible ? Use our model to find the solution then make a diagram.

Hint : see the line graph in exercise 8 page 54

Lessons 8

Vocabulary : DNA, Chromosomes, cells

I) Human heredity : the alleles transmittance

Exercise

Think and use your knowledge

Daddy’s blood type is O, mummy’s blood type is A and their child’s blood type is O.
1) Indicate the alleles for the blood type gene in the pair of chromosome 9 for each person
2) Use your knowledge about reproduction, draw a sperm cell, an egg cell and a fertilized egg. Indicate in them, the allele(s) defined in question 1)
3) What problem emerges now ? Offer an hypothesis

Research

At page 57, select and write down informations that could confirm your hypothesis

Lesson 9

Each sex cell has only 23 chromosomes instead of 46. They join to give a fertilized egg cell, that will divide many times to become an embryo and then a new individual.
Our father and our mother gave us randomly half of their alleles (their genetic information). This new combination of alleles makes us unique.
In each pair of chromosomes, one comes from our mother, the other one comes from our father.